Onboard controller for multistate windows

ABSTRACT

Onboard EC window controllers are described. The controllers are configured in close proximity to the EC window, for example, within the IGU. The controller may be part of a window assembly, which includes an IGU having one or more EC panes, and thus does not have to be matched with the EC window, and installed, in the field. The window controllers described herein have a number of advantages because they are matched to the IGU containing one or more EC devices and their proximity to the EC panes of the window overcomes a number of problems associated with conventional controller configurations.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 13/049,750, titled “ONBOARD CONTROLLER FORMULTISTATE WINDOWS,” and filed on Mar. 16, 2011, and is acontinuation-in-part of and claims priority to U.S. patent applicationSer. No. 12/971,576, titled “WIRELESS POWERED ELECTROCHROMIC WINDOWS,”and filed on Dec. 17, 2010, which claims priority to U.S. ProvisionalApplication Ser. No. 61/289,319, filed Dec. 22, 2009, all of which areherein incorporated by reference.

The application is related to U.S. patent application Ser. No.13/049,756, titled “MULTIPURPOSE CONTROLLER FOR MULTISTATE WINDOWS,” andfiled on Mar. 16, 2011, which is incorporated herein by reference in itsentirety and for all purposes.

FIELD

The invention relates generally to electrochromic devices, moreparticularly to controllers for electrochromic windows.

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device (EC)of the window will cause them to darken; reversing the voltage causesthem to lighten. This capability allows control of the amount of lightthat passes through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

While electrochromism was discovered in the 1960's, EC devices, andparticularly EC windows, still unfortunately suffer various problems andhave not begun to realize their full commercial potential despite manyrecent advancements in EC technology, apparatus and related methods ofmaking and/or using EC devices.

SUMMARY

“Localized” controllers for EC windows are described. In someembodiments, a localized controller is an “onboard” or “in situ”controller, where the window controller is part of a window assembly andthus does not have to be matched with a window and installed in thefield. The window controllers have a number of advantages because theyare matched to an IGU containing one or more EC devices. Localizedcontrollers eliminate the problematic issue of varying wire length fromEC window to controller in conventional systems. In some embodiments, anin situ controller is incorporated into the IGU and/or the window frameprior to installation. As discussed in more detail below, a number ofadvantages and synergies are realized by localized EC windowcontrollers, in particular, where the controller is part of a windowassembly.

One embodiment is a window assembly including: at least oneelectrochromic (EC) pane; and a window controller configured to controlthe at least one EC pane of an IGU of the window assembly. Windowcontrollers described herein can control more than one EC pane,including two, three or more EC panes in a single EC window. In oneembodiment, the window controller is not positioned within the viewablearea of the IGU of the window assembly.

In one embodiment, a window controller described herein can include: apower converter configured to convert a low voltage to the powerrequirements of the at least one EC pane; a communication circuit forreceiving and sending commands to and from a remote controller (forexample via a communication bus and/or a wireless transmitter), andreceiving and sending input to and from; a microcontroller including alogic for controlling the at least one EC pane based at least in part byinput received from one or more sensors; and a driver circuit forpowering the at least one EC device. The communication circuit (i.e.,communication interface) can include wireless capability. The windowcontroller may also include a redundant driver circuit, one or moresensors, an RFID tag, and/or memory such as solid state serial memory(e.g. I2C or SPI) which may optionally be a programmable memory. Whenthe EC window's IGU includes more than one EC pane, the controller logiccan be configured to independently control each of the two EC panes.Particularly useful EC panes include all solid state and inorganic ECdevices.

Another embodiment is an EC pane with an associated EC controller, wherethe associated EC controller is mounted on the EC pane. The ECcontroller may or may not extend beyond the outer perimeter of the ECpane.

Another embodiment is an IGU including a controller as described herein.Onboard controllers may be located between the panes of the IGU. In oneembodiment, the controller is mounted within the secondary seal of theIGU and may or may not extend past the outer perimeter of the panesmaking up the IGU. In one embodiment, the shape and size of thecontrollers is configured to reside in between the panes of the IGU andmay span one or more sides of the secondary seal, around the perimeterof the primary seal. Localized controllers may be relatively small, forexample, having dimensions of 6 inches by 1 inch by 1 inch, or less, oneach dimension. In one embodiment, the controller has dimensions of 5inches by ¾ inches by ⅝ inches, or less, on each dimension.

Another embodiment is an EC window controller as described herein.

Yet another embodiment is a network of EC windows including localized,particularly in situ or onboard, window controllers as described herein.

Another embodiment is a window unit including: a substantiallytransparent substrate having an electrochromic device disposed thereon;and a controller integrated with the substrate in the window unit forproviding optical switching control for the electrochromic device.“Integration with the substrate” means that the controller is in closeproximity to, for example within 1 meter or less, or for example mountedon the substrate bearing the EC device. In one embodiment, the windowunit further includes: a second substantially transparent substrate; anda sealing separator between the first and second substantiallytransparent substrates, which sealing separator defines, together withthe first and second substantially transparent substrates, an interiorregion that is thermally insulating. In one embodiment, the controlleris embedded in the sealing separator. In one embodiment, the controllerincludes control logic for directing the electrochromic device to switchbetween three or more optical states. In one embodiment, the controlleris configured to prevent the electrochromic device from being connectedto in a reverse polarity mode to an external power source. In variousembodiments, the controller is configured to be powered by a sourcedelivering between about 2 and 10 volts. The controller may includewireless communication and/or powering functions. The window unit mayfurther include a sensor, for example housed in the window frame, incommunication with the controller. Exemplary sensors include thermalsensors and optical sensors. In one embodiment, the sensor can detect abroken lead for delivering power to the electrochromic device. Thecontroller may include a chip, a card or a board, for example a fieldprogrammable gate array.

These and other features and advantages will be described in furtherdetail below, with reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description can be more fully understood whenconsidered in conjunction with the drawings in which:

FIG. 1A depicts conventional fabrication of an IGU including an EC paneand incorporation into a window assembly.

FIG. 1B depicts a conventional wiring scheme for EC window controllers.

FIG. 2A is a schematic of a window assembly with an IGU having anonboard controller.

FIG. 2B is a schematic of an onboard window controller.

FIG. 3 depicts a wiring scheme including EC windows with onboard windowcontrollers.

FIG. 4 depicts a distributed network of EC window controllers withconventional end or leaf controllers as compared to a distributednetwork with EC windows having onboard controllers

FIG. 5A is a schematic of an onboard window controller.

FIG. 5B depicts a user interface for localized controllers describedherein.

FIGS. 6A and 6B depict automated and non-automated daisy chainconfigurations for EC windows and controllers, respectively.

DETAILED DESCRIPTION

A “localized” controller, as described herein, is a window controllerthat is associated with, and controls, a single EC window. An EC windowmay include one, two, three or more individual EC panes (an EC device ona transparent substrate). The controller is generally configured inclose proximity to the EC window. In certain embodiments, this meansthat the controller is, for example, within 1 meter of the EC windowwhen controller is installed, in one embodiment, within 0.5 meter, inyet another embodiment, within 0.25 meter. In some embodiments, thewindow controller is an “in situ” controller; that is, the controller ispart of a window assembly, which includes an IGU having one or more ECpanes, and thus does not have to be matched with the EC window, andinstalled, in the field. The controller may be installed in the windowframe of a window unit, or be part of the IGU, for example, mountedbetween panes of the IGU.

It should be understood that while the disclosed embodiments focus onelectrochromic windows, the concepts may apply to other types ofswitchable optical devices such as liquid crystal devices and suspendedparticle devices.

The window controllers described herein have a number of advantagesbecause they are matched to the IGU containing one or more EC devices.In one embodiment, the controller is incorporated into the IGU and/orthe window frame prior to installation of the EC window. In oneembodiment, the controller is incorporated into the IGU and/or thewindow frame prior to leaving the manufacturing facility. In oneembodiment, the controller is incorporated into the IGU, substantiallywithin the secondary seal. Having the controller as part of an IGUand/or a window assembly, the IGU can be characterized using logic andfeatures of the controller that travels with the IGU or window unit. Forexample, when a controller is part of the IGU assembly, in the event thecharacteristics of the EC device(s) change over time, thischaracterization function can be used, for example, to redirect intowhich product the IGU will be incorporated. In another example, ifalready installed in an EC window unit, the logic and features of thecontroller can be used to calibrate the control parameters to match theintended installation, and for example if already installed, the controlparameters can be recalibrated to match the performance characteristicsof the EC pane(s).

In this application, an “IGU” includes two substantially transparentsubstrates, for example, two panes of glass, where at least onesubstrate includes an EC device disposed thereon, and the panes have aseparator disposed between them. An IGU is typically hermeticallysealed, having an interior region that is isolated from the ambientenvironment. A “window assembly” includes an IGU, and may includeelectrical leads for connecting the IGU's one or more EC devices to avoltage source, switches and the like, as well as a frame that supportsthe IGU and related wiring.

For context, a discussion of conventional window controller technologyfollows. FIG. 1A depicts an EC window fabrication and control scheme,100. An EC pane, 105, having an EC device (not shown, but for example onsurface A) and bus bars, 110, which power the EC device, is matched withanother glass pane, 115. During fabrication of IGU, 125, a separator,120, is sandwiched in between and registered with substrates 105 and115. The IGU 125 has an associated interior space defined by the facesof the substrates in contact with separator 120 and the interiorsurfaces of the separator. Separator 110 is typically a sealingseparator, that is, includes a spacer and sealing between the spacer andeach substrate where they adjoin in order to hermetically seal theinterior region and thus protect the interior from moisture and thelike. Typically, once the glass panes are sealed to the separator,secondary sealing may be applied around the perimeter edges of the IGUin order to impart further sealing from the ambient, as well as furtherstructural rigidity to the IGU. The IGU 125 must be wired to acontroller via wires, 130. The IGU is supported by a frame to create awindow assembly, 135. Window assembly 135 is connected, via wires 130,to a controller, 140. Controller 140 may also be connected to one ormore sensors in the frame via communication lines 145.

As depicted in FIG. 1A, conventional EC window controllers are not partof the window assembly itself and thus it is required that thecontrollers are installed outside of the IGU and/or window assembly.Also, conventional window controllers are calibrated to the EC windowthey control at the installation site, putting more burden on theinstaller. Consequently, there are more parts to ship from themanufacturer to the installation site, and this has associated trackingpitfalls, for example, mismatching of window and associated controller.Mismatched controller and window can cause installation delays as wellas damage to the controller and/or IGU. All these factors contribute tohigher cost of EC windows. Also, since conventional controllers areremotely located, long and differing lengths of low voltage (e.g. lessthan 10 v DC) wiring and thus are wired to one or more EC windows aspart of the installation of the EC windows. For example, referring toFIG. 1B, controllers 140 each control an EC window 135. Typically thecontrollers are located proximate to a single location and so lowvoltage wiring 130 is of varying length. This is true even if there isonly one controller that controls multiple windows. There are associatedcurrent drop offs and losses due to this long wiring. Also, since thecontroller is located remotely, any control feedback or diagnosticsensors mounted in the window assembly require separate wiring to be runto the controller—increasing cost and complexity of installation. Also,any identification numbers on the IGU are hidden by the frame and maynot be easily accessible, which makes it problematic to check IGUinformation, for example, checking warranty or other vendor information.

In one embodiment, localized controllers are installed as part of thewall of the room in which the associated window's or IGU's will beinstalled. That is, the controllers are installed in the framing and/orwall materials proximate (according to the distances described herein)to where their associated window units or IGU's will be installed. Thismay be in materials that will ultimately be part of the wall, where aseparate window frame and IGU (a window unit) is to be installed, or thecontroller may be installed in framing materials that will serve, atleast partially, as the frame for the EC window, where the IGU's areinstalled into the framing to complete an IGU and controller proximitymatching. Thus, one embodiment is a method of installing an EC windowand associated controller unit into a wall, the method including (a)installing the associated controller unit into a wall, and (b)installing either an EC window unit which includes a window frame of theEC window, or installing an IGU, where the wall framing serves as theframe for the EC window.

In one embodiment, controllers described herein are part of a windowassembly. One embodiment is a window unit including: a substantiallytransparent substrate having an electrochromic device disposed thereon;and a controller integrated with the substrate in the window unit forproviding optical switching control for the electrochromic device. Inone embodiment, the window unit further includes: a second substantiallytransparent substrate; and a sealing separator between the first andsecond substantially transparent substrates, which sealing separatordefines, together with the first and second substantially transparentsubstrates, an interior region that is thermally insulating. In oneembodiment, the controller is embedded in the sealing separator. In oneembodiment, the controller includes control logic for directingelectrochromic device to switch between three or more optical states. Inone embodiment, the controller is configured to prevent theelectrochromic device from being connected to in a reverse polarity modeto an external power source. In one embodiment, the controller isconfigured to be powered by a source delivering between about 2 and 10volts. There can be included in the window assembly, supply lines fordelivering both power and communications to the controller or only powerwhere the controller includes wireless communication capability.

In one embodiment, the window assembly includes an IGU with at least oneEC pane; and a window controller configured to control the at least oneEC pane of the IGU of the window assembly. Preferably, but notnecessarily, the window controller is not positioned within the viewablearea of the IGU. In one embodiment, the window controller is positionedoutside of the primary seal of the IGU. The controller could be in thewindow frame and/or in between the panes of the IGU. In one embodiment,the window controller is included with the IGU. That is, the IGU, whichincludes a “window unit” including two (or more) panes and a separator,also includes the window controller. In one embodiment, the windowcontroller is positioned at least partially between the individual panesof the IGU, outside of the primary seal. In one embodiment, the windowcontroller may span a distance from a point between the two panes of theIGU and a point beyond the panes, for example, so that the portion thatextends beyond the panes resides in, at least partially, the frame ofthe window assembly.

In one embodiment, the window controller is in between and does notextend beyond the individual panes of the IGU. This configuration isdesirable because the window controller can be, for example, wired tothe EC device(s) of the EC panes of the IGU and included in thesecondary sealing of the IGU. This incorporates the window controllerinto the secondary seal; although it may be partially exposed to theambient for wiring purposes. In one embodiment, the controller may onlyneed a power socket exposed, and thus be “plugged in” to a low voltagesource (for example a 24 v source) because the controller communicatesotherwise via wireless technology and/or through the power lines (e.g.like Ethernet over power lines). The wiring from the controller to theEC device, for example between 2 v and 10 v, is minimized due to theproximity of the controller to the EC device.

Electrochromic windows which are suitable for use with controllersdescribed herein include, but are not limited to, EC windows having one,two or more electrochromic panes. Windows having EC panes with ECdevices thereon that are all solid state and inorganic EC devices areparticularly well suited for controllers described herein due to theirexcellent switching and transition characteristics as well as lowdefectivity. Such windows are described in the following U.S. patentapplication Ser. No. 12/645,111, entitled, “Fabrication ofLow-Defectivity Electrochromic Devices,” filed on Dec. 22, 2009 andnaming Mark Kozlowski et al. as inventors; Ser. No. 12/645,159,entitled, “Electrochromic Devices,” filed on Dec. 22, 2009 and namingZhongchun Wang et al. as inventors; Ser. Nos. 12/772,055 and 12/772,075,each filed on Apr. 30, 2010, and in U.S. patent application Ser. Nos.12/814,277 and 12/814,279, each filed on Jun. 11, 2010—each of thelatter four applications is entitled “Electrochromic Devices,” eachnames Zhongchun Wang et al. as inventors; Ser. No. 12/851,514, filed onAug. 5, 2010, and entitled “Multipane Electrochromic Windows,” each ofwhich is incorporated by reference herein for all purposes. Asmentioned, the controllers disclosed herein may useful for switchableoptical devices that are not electrochromic devices. Such alternativedevices include liquid crystal devices and suspended particle devices.

In certain embodiments, the EC device or devices of the EC windows facethe interior region of the IGU to protect them from the ambient. In oneembodiment, the EC window includes a two-state EC device. In oneembodiment, the EC window has only one EC pane, the pane may have atwo-state (optical) EC device (colored or bleached states) or a devicethat has variable transitions. In one embodiment, the window includestwo EC panes, each of which includes a two-state device thereon and theIGU has two optical states, in another embodiment, the IGU has fouroptical states. In one embodiment, the four optical states are: i)overall transmittance of between about 60% and about 90%; ii) overalltransmittance of between about 15% and about 30%; iii) overalltransmittance of between about 5% and about 10%; and iv) overalltransmittance of between about 0.1% and about 5%. In one embodiment, theEC window has one pane with an EC device having two states and anotherpane with an EC device with variable optical state capability. In oneembodiment, the EC window has two EC panes, each having an EC devicewith variable optical state capability. In one embodiment, the EC windowincludes three or more EC panes.

In certain embodiments, the EC windows are low-defectivity windows. Inone embodiment, the total number of visible defects, pinholes andshort-related pinholes created from isolating visible short-relateddefects in an EC device of the EC window is less than about 0.1 defectsper square centimeter, in another embodiment, less than about 0.045defects per square centimeter.

FIG. 2A depicts a window assembly, 200, including a window frame, 205.The viewable area of the window unit is indicated on the figure, insidethe perimeter of frame 205. As indicated by dotted lines, inside frame205, is an IGU, 210, which includes two glass panes separated by asealing separator, 215, shaded in gray. Window controller, 220, isbetween the glass panes of IGU 210 and, in this example, does not extendbeyond the perimeter of the glass panes of the IGU. The windowcontroller need not be incorporated into a single enclosure as depicted,and need not be along a single edge of the IGU. For example, in oneembodiment, the controller resides along two, three or four edges of theIGU, in some instances, all within the secondary seal zone. In someembodiments, the window controller can extend beyond the perimeter ofthe IGU and into the frame of the window assembly.

There are advantages to having the window controller positioned in theframe of the window assembly, particularly in the secondary seal zone ofan IGU, some of these include: 1) wiring from the controller to one ormore EC devices of the IGU panes is very short, and consistent fromwindow to window for a given installation, 2) any custom pairing andtuning of controller and IGU can be done at the factory without chancesof mis-pairing controller and window in the field, 3) even if there areno mismatches, there are fewer parts to ship, track and install, 4)there is no need for a separate housing and installation for thecontroller, because the components of the controller can be incorporatedinto the secondary seal of the IGU, 5) wiring coming to the window canbe higher voltage wiring, for example 24V or 48V, and thus line lossesseen in lower voltage lines (e.g. less than 10V DC) are obviated, 6)this configuration allows in-situ connection to control feedback anddiagnostic sensors, obviating the need for long wiring to remotecontrollers, and 7) the controller can store pertinent information aboutthe IGU, for example using an RFID tag and/or memory such as solid stateserial memory (e.g. I2C or SPI) which may optionally be programmable.Stored information may include, for example, the manufacturing date,batch ID, window size, warranty information, EC device cycle count,current detected window condition (e.g., applied voltage, temperature, %Tvis), window drive configuration parameters, controller zonemembership, and like information, which will be further described below.These benefits save time, money and installation downtime, as well asproviding more design flexibility for control and feedback sensing. Moredetails of the window controller are described below.

One embodiment is a window assembly (or IGU) having at least one ECpane, where the window assembly (or IGU) includes a window controller.In one embodiment, the window controller includes: a power converterconfigured to convert a low voltage, for example 24V, to the powerrequirements of said at least one EC pane, for example between 2V and10V; a communication circuit for receiving and sending commands to andfrom a remote controller, and receiving and sending input to and from; amicrocontroller comprising a logic for controlling said at least one ECpane based at least in part by input received from one or more sensors;and a driver circuit for powering said at least one EC device.

FIG. 2B, depicts an example window controller 220 in some detail.Controller 220 includes a power converter configured to convert a lowvoltage to the power requirements of an EC device of an EC pane of anIGU. This power is typically fed to the EC device via a driver circuit(power driver). In one embodiment, controller 220 has a redundant powerdriver so that in the event one fails, there is a back up and thecontroller need not be replaced or repaired.

Controller 220 also includes a communication circuit (labeled“communication” in FIG. 2B) for receiving and sending commands to andfrom a remote controller (depicted in FIG. 2B as “master controller”).The communication circuit also serves to receive and send input to andfrom a microcontroller. In one embodiment, the power lines are also usedto send and receive communications, for example, via protocols such asethernet. The microcontroller includes a logic for controlling the atleast one EC pane based, at least in part, by input received from one ormore sensors. In this example sensors 1-3 are, for example, external tocontroller 220, for example in the window frame or proximate the windowframe. In one embodiment, the controller has at least one or moreinternal sensors. For example, controller 220 may also, or in thealternative, have “onboard” sensors 4 and 5. In one embodiment, thecontroller uses the EC device as a sensor, for example, by usingcurrent-voltage (IN) data obtained from sending one or more electricalpulses through the EC device and analyzing the feedback. This type ofsensing capability is described in U.S. patent application Ser. No.13/049,756, naming Brown et al. as inventors, titled “MultipurposeController for Multistate Windows,” which is incorporated by referenceherein for all purposes.

In one embodiment, the controller includes a chip, a card or a boardwhich includes appropriate logic, programmed and/or hard coded, forperforming one or more control functions. Power and communicationfunctions of controller 220 may be combined in a single chip, forexample, a programmable logic device (PLD) chip, field programmable gatearray (FPGA) or similar device. Such integrated circuits can combinelogic, control and power functions in a single programmable chip. In oneembodiment, where the EC window (or IGU) has two EC panes, the logic isconfigured to independently control each of the two EC panes. In oneembodiment, the function of each of the two EC panes is controlled in asynergistic fashion, that is, so that each device is controlled in orderto complement the other. For example, the desired level of lighttransmission, thermal insulative effect, and/or other property arecontrolled via combination of states for each of the individual devices.For example, one EC device may have a colored state while the other isused for resistive heating, for example, via a transparent electrode ofthe device. In another example, the two EC device's colored states arecontrolled so that the combined transmissivity is a desired outcome.

Controller 220 may also have wireless capabilities, such as control andpowering functions. For example, wireless controls, such as Rf and/or IRcan be used as well as wireless communication such as Bluetooth, WiFi,Zigbee, EnOcean and the like to send instructions to the microcontrollerand for the microcontroller to send data out to, for example, otherwindow controllers and/or a building management system (BMS). Wirelesscommunication can be used in the window controller for at least one ofprogramming and/or operating the EC window, collecting data from the ECwindow from sensors as well as using the EC window as a relay point forwireless communication. Data collected from EC windows also may includecount data such as number of times an EC device has been activated(cycled), efficiency of the EC device over time, and the like. Each ofthese wireless communication features is described in U.S. patentapplication Ser. No. 13/049,756, naming Brown et al. as inventors,titled “Multipurpose Controller for Multistate Windows,” which wasincorporated by reference above.

Also, controller 220 may have wireless power function. That is,controller 220 may have one or more wireless power receivers, thatreceive transmissions from one or more wireless power transmitters andthus controller 220 can power the EC window via wireless powertransmission. Wireless power transmission includes, for example but notlimited to, induction, resonance induction, radio frequency powertransfer, microwave power transfer and laser power transfer. In oneembodiment, power is transmitted to a receiver via radio frequency, andthe receiver converts the power into electrical current utilizingpolarized waves, for example circularly polarized, ellipticallypolarized and/or dual polarized waves, and/or various frequencies andvectors. In another embodiment, power is wirelessly transferred viainductive coupling of magnetic fields. Exemplary wireless powerfunctions of electrochromic windows is described in U.S. patentapplication Ser. No. 12/971,576, filed Dec. 17, 2010, titled “WirelessPowered Electrochromic Windows”, and naming Robert Rozbicki as inventor,which is incorporated by reference herein in its entirety.

Controller 220 may also include an RFID tag and/or memory such as solidstate serial memory (e.g. I2C or SPI) which may optionally be aprogrammable memory. Radio-frequency identification (RFID) involvesinterrogators (or readers), and tags (or labels). RFID tags usecommunication via electromagnetic waves to exchange data between aterminal and an object, for example, for the purpose of identificationand tracking of the object. Some RFID tags can be read from severalmeters away and beyond the line of sight of the reader.

Most RFID tags contain at least two parts. One is an integrated circuitfor storing and processing information, modulating and demodulating aradio-frequency (Rf) signal, and other specialized functions. The otheris an antenna for receiving and transmitting the signal.

There are three types of RFID tags: passive RFID tags, which have nopower source and require an external electromagnetic field to initiate asignal transmission, active RFID tags, which contain a battery and cantransmit signals once a reader has been successfully identified, andbattery assisted passive (BAP) RFID tags, which require an externalsource to wake up but have significant higher forward link capabilityproviding greater range. RFID has many applications; for example, it isused in enterprise supply chain management to improve the efficiency ofinventory tracking and management.

In one embodiment, the RFID tag or other memory is programmed with atleast one of the following types of data: warranty information,installation information, vendor information, batch/inventoryinformation, EC device/IGU characteristics, EC device cyclinginformation and customer information. Examples of EC devicecharacteristics and IGU characteristics include, for example, windowvoltage (V_(W)), window current (I_(W)), EC coating temperature(T_(EC)), glass visible transmission (% T_(vis)), % tint command(external analog input from BMS), digital input states, and controllerstatus. Each of these represents upstream information that may beprovided from the controller to a BMS or window management system orother building device. The window voltage, window current, windowtemperature, and/or visible transmission level may be detected directlyfrom sensors on the windows. The % tint command may be provided to theBMS or other building device indicating that the controller has in facttaken action to implement a tint change, which change may have beenrequested by the building device. This can be important because otherbuilding systems such as HVAC systems might not recognize that a tintaction is being taken, as a window may require a few minutes (e.g., 10minutes) to change state after a tint action is initiated. Thus, an HVACaction may be deferred for an appropriate period of time to ensure thatthe tinting action has sufficient time to impact the buildingenvironment. The digital input states information may tell a BMS orother system that a manual action relevant to the smart window has beentaken. See block 504 in FIG. 5A. Finally, the controller status mayinform the BMS or other system that the controller in question isoperational, or not, or has some other status relevant to its overallfunctioning.

Examples of downstream data from a BMS or other building system that maybe provided to the controller include window drive configurationparameters, zone membership (e.g. what zone within the building is thiscontroller part of), % tint value, digital output states, and digitalcontrol (tint, bleach, auto, reboot, etc.). The window drive parametersmay define a control sequence (effectively an algorithm) for changing awindow state. Examples of window drive configuration parameters includebleach to color transition ramp rate, bleach to color transitionvoltage, initial coloration ramp rate, initial coloration voltage,initial coloration current limit, coloration hold voltage, colorationhold current limit, color to bleach transition ramp rate, color tobleach transition voltage, initial bleach ramp rate, initial bleachvoltage, initial bleach current limit, bleach hold voltage, bleach holdcurrent limit. Examples of the application of such window driveparameters are presented in U.S. patent application Ser. No. 13/049,623,titled “Controlling Transitions In Optically Switchable Devices,” whichis incorporated herein by reference in its entirety.

The % tint value may be an analog or digital signal sent from the BMS orother management device instructing the onboard controller to place itswindow in a state corresponding to the % tint value. The digital outputstate is a signal in which the controller indicates that it has takenaction to begin tinting. The digital control signal indicates that thecontroller has received a manual command such as would be received froman interface 504 as shown in FIG. 5B. This information can be used bythe BMS to, for example, log manual actions on a per window basis.

In one embodiment, a programmable memory is used in controllersdescribed herein. This programmable memory can be used in lieu of, or inconjunction with, RFID technology. Programmable memory has the advantageof increased flexibility for storing data related to the IGU to whichthe controller is matched.

Advantages of “localized” controllers, particularly “in situ” or“onboard” controllers, described herein are further described inrelation to FIGS. 3 and 4. FIG. 3 depicts an arrangement, 300, includingEC windows, 305, each with an associated localized or onboard windowcontroller (not shown). FIG. 3 illustrates that with onboardcontrollers, wiring, for example for powering and controlling thewindows, is very simplified versus, for example, conventional wiring asdepicted in FIG. 1B. In this example, a single power source, for examplelow voltage 24V, can be wired throughout a building which includeswindows 305. There is no need to calibrate various controllers tocompensate for variable wiring lengths and associated lower voltage(e.g. less than 10V DC) to each of many distant windows. Because thereare not long runs of lower voltage wiring, losses due to wiring lengthare reduced or avoided, and installation is much easier and modular. Ifthe window controller has wireless communication and control, or usesthe power lines for communication functions, for example ethernet, thenonly a single voltage power wiring need be strung through the building.If the controller also has wireless power transmission capabilities,then no wiring is necessary, since each window has its own controller.

FIG. 4 depicts a distributed network, 400, of EC window controllers withconventional end or leaf controllers as compared to a distributednetwork, 420, with EC windows having onboard controllers. Such networksare typical in large commercial buildings that may include smartwindows.

In network 400, a master controller controls a number of intermediatecontrollers, 405 a and 405 b. Each of the intermediate controllers inturn controls a number of end or leaf controllers, 410. Each ofcontrollers 410 controls an EC window. Network 400 includes the longspans of lower DC voltage, for example a few volts, wiring andcommunication cables from each of leaf controllers 410 to each window430. In comparison, by using onboard controllers as described herein,network 420 eliminates huge amounts of lower DC voltage wiring betweeneach end controller and its respective window. Also this saves anenormous amount of space that would otherwise house leaf controllers410. A single low voltage, e.g. from a 24 v source, is provided to allwindows in the building, and there is no need for additional lowervoltage wiring or calibration of many windows with their respectivecontrollers. Also, if the onboard controllers have wirelesscommunication function or capability of using the power wires, forexample as in ethernet technology, there is no need for extracommunication lines between intermediate controllers 405 a and 405 b andthe windows.

FIG. 5A is a schematic depiction of an onboard window controllerconfiguration, 500, including interface for integration of EC windowsinto, for example, a residential system or a building management system.A voltage regulator accepts power from a standard 24 v AC/DC source. Thevoltage regulator is used to power a microprocessor (μP) as well as apulse width modulated (PWM) amplifier which can generate current at highand low output levels, for example, to power an associated smart window.A communications interface allows, for example, wireless communicationwith the controller's microprocessor. In one embodiment, thecommunication interface is based on established interface standards, forexample, in one embodiment the controller's communication interface usesa serial communication bus which may be the CAN 2.0 physical layerstandard introduced by Bosch widely used today for automotive andindustrial applications. “CAN” is a linear bus topology allowing for 64nodes (window controllers) per network, with data rates of 10 kbps to 1Mbps, and distances of up to 2500 m. Other hard wired embodimentsinclude MODBUS, LonWorks™, power over Ethernet, BACnet MS/TP, etc. Thebus could also employ wireless technology (e.g. Zigbee, Bluetooth,etc.).

In the depicted embodiment, the controller includes a discreteinput/output (DIO) function, where a number of inputs, digital and/oranalog, are received, for example, tint levels, temperature of ECdevice(s), % transmittance, device temperature (for example from athermistor), light intensity (for example from a LUX sensor) and thelike. Output includes tint levels for the EC device(s). Theconfiguration depicted in FIG. 5A is particularly useful for automatedsystems, for example, where an advanced BMS is used in conjunction withEC windows having EC controllers as described herein. For example, thebus can be used for communication between a BMS gateway and the ECwindow controller communication interface. The BMS gateway alsocommunicates with a BMS server.

Some of the functions of the discrete I/O will now be described.

DI-TINT Level bit 0 and DI-TINT Level bit 1: These two inputs togethermake a binary input (2 bits or 2²=4 combinations; 00, 01, 10 and 11) toallow an external device (switch or relay contacts) to select one of thefour discrete tint states for each EC window pane of an IGU. In otherwords, this embodiment assumes that the EC device on a window pane hasfour separate tint states that can be set. For IGUs containing twowindow panes, each with its own four-state TINT Level, there may be asmany as eight combinations of binary input. See U.S. patent applicationSer. No. 12/851,514, filed on Aug. 5, 2010 and previously incorporatedby reference. In some embodiments, these inputs allow users to overridethe BMS controls (e.g. untint a window for more light even though theBMS wants it tinted to reduce heat gain).

AI-EC Temperature: This analog input allows a sensor (thermocouple,thermister, RTD) to be connected directly to the controller for thepurpose of determining the temperature of the EC coating. Thustemperature can be determined directly without measuring current and/orvoltage at the window. This allows the controller to set the voltage andcurrent parameters of the controller output, as appropriate for thetemperature.

AI-Transmittance: This analog input allows the controller to measurepercent transmittance of the EC coating directly. This is useful for thepurpose of matching multiple windows that might be adjacent to eachother to ensure consistent visual appearance, or it can be used todetermine the actual state of the window when the control algorithmneeds to make a correction or state change. Using this analog input, thetransmittance can be measured directly without inferring transmittanceusing voltage and current feedback.

AI-Temp/Light Intensity: This analog input is connected to an interiorroom or exterior (to the building) light level or temperature sensor.This input may be used to control the desired state of the EC coatingseveral ways including the following: using exterior light levels, tintthe window (e.g. bright outside, tint the window or vice versa); usingand exterior temperature sensor, tint the window (e.g. cold outside dayin Minneapolis, untint the window to induce heat gain into the room orvice versa, warm day in Phoenix, tint the widow to lower heat gain andreduce air conditioning load).

AI-% Tint: This analog input may be used to interface to legacy BMS orother devices using 0-10 volt signaling to tell the window controllerwhat tint level it should take. The controller may choose to attempt tocontinuously tint the window (shades of tint proportionate to the 0-10volt signal, zero volts being fully untinted, 10 volts being fullytinted) or to quantize the signal (0-0.99 volt means untint the window,1-2.99 volts means tint the window 5%, 3-4.99 volts equals 40% tint, andabove 5 volts is fully tinted). When a signal is present on thisinterface it can still be overridden by a command on the serialcommunication bus instructing a different value.

DO-TINT LEVEL bit 0 and bit 1: This digital input is similar to DI-TINTLevel bit 0 and DI-TINT Level bit 1. Above, these are digital outputsindicating which of the four states of tint a window is in, or beingcommanded to. For example if a window were fully tinted and a user walksinto a room and wants them clear, the user could depress one of theswitches mentioned and cause the controller to begin untinting thewindow. Since this transition is not instantaneous, these digitaloutputs will be alternately turned on and off signaling a change inprocess and then held at a fixed state when the window reaches itscommanded value.

FIG. 5B depicts an onboard controller configuration 502 having a userinterface. For example where automation is not required, the EC windowcontroller, for example as depicted in FIG. 5A, can be populated withoutthe PWM components and function as I/O controller for an end user where,for example, a keypad, 504, or other user controlled interface isavailable to the end user to control the EC window functions. The ECwindow controller and optionally I/O controllers can be daisy chainedtogether to create networks of EC windows, for automated andnon-automated EC window applications.

FIGS. 6A and 6B depict automated and non-automated daisy chainconfigurations for EC windows and EC window controllers describedherein. Where automation is desired (see FIG. 6A), for example, a busallows setting and monitoring individual window parameters and relayingthat information though the network controller directly to a BMS via,for example, an Ethernet gateway. In one embodiment, a networkcontroller contains an embedded web server for local control viaEthernet from, for example, a PC or smart phone. In one embodiment,network commissioning is done via a controller's web server and a windowscheduler, for example, where HVAC and lighting programs execute locallyon the controller. In one embodiment, network controllers can wirelesslyconnect to each other via, for example, a Zigbee mesh network, allowingfor expansion for large numbers of windows or to create control zoneswithin a building using sets of windows. As depicted in FIG. 6B, when noautomation is required, window control is accomplished through an I/Ocontroller as described above. In one embodiment, there is also a masteroverride included. In one embodiment, a network, for example a daisychain network as depicted in FIG. 6A or 6B, is constructed onsite (fieldwired). In another embodiment, commercially available cabling products(no tooling required) are used to construct a network of windowcontrollers, for example, interconnects, cable assemblies, tees, hubsand the like are widely available from commercial suppliers.

Although the foregoing invention has been described in some detail tofacilitate understanding, the described embodiments are to be consideredillustrative and not limiting. It will be apparent to one of ordinaryskill in the art that certain changes and modifications can be practicedwithin the scope of the appended claims.

What is claimed is:
 1. A network comprising: (a) two or more window assemblies, each comprising: at least one electrochromic pane provided in an insulated glass unit (IGU), the IGU comprising the electrochromic pane, at least one additional pane, a sealing separator between the electrochromic pane and the at least one additional pane, and a secondary seal around the sealing separator; a window controller comprising (i) circuitry for processing digital signals including discrete tint values received from the network, and (ii) memory storing drive configuration parameters for driving tint state transitions in the at least one electrochromic pane, wherein the window controllers are positioned at least partially between the electrochromic pane and the additional pane of the IGU in the secondary seal; (b) a network controller communicatively coupled to the window controller of each of the two or more window assemblies and configured to send input signals to each of the window controllers, the input signals comprising the discrete tint values, and wherein each of the window controllers is configured to control said at least one electrochromic pane of its associated window assembly based on the discrete tint value received from the network controller and the stored drive configuration parameters particular to each window assembly; and (c) an electrical path connecting the window controllers in a linear bus topology.
 2. The network of claim 1, further comprising a building management system communicatively coupled to each of the window controllers.
 3. The network of claim 1, further comprising a direct electrical path between the network controller and each window assembly that does not go through other window assemblies.
 4. The network of claim 3, wherein the electrical path delivers both power and control information.
 5. The network of claim 3, wherein the electrical path provides low voltage power.
 6. The network of claim 5, wherein each window assembly further comprises a power converter to convert a low voltage to a power requirement of the at least one electrochromic pane.
 7. The network of claim 1, wherein the window controllers are configured to send one or more electrical pulses through the window assembly and analyze the feedback.
 8. The network of claim 1, wherein the window controllers comprise wireless power receivers.
 9. The network of claim 1, wherein control information is distributed through wireless communication.
 10. The network of claim 1, wherein the network controller comprises an embedded web server.
 11. The network of claim 10, wherein the embedded web server may be controlled via Ethernet by a PC or smartphone.
 12. The network of claim 1, wherein the window assemblies further comprise an optical and/or thermal sensor connected to the window controller.
 13. The network of claim 1, wherein the window controllers are positioned outside a primary seal of the IGU.
 14. The network of claim 1, wherein the window controllers are positioned around two or more sides of the perimeter of the IGU.
 15. The network of claim 1, wherein the window controllers are positioned along only one side of the perimeter of the IGU.
 16. The network of claim 1, wherein the window controllers reside entirely between two panes of the IGU.
 17. The network of claim 1, wherein the window controllers are incorporated into the IGU, substantially within the secondary seal.
 18. The network of claim 1, wherein each of the window controllers extend beyond a perimeter of the IGU and into a frame that holds the IGU.
 19. The network of claim 1, wherein the window controllers are embedded in the sealing separator.
 20. The network of claim 18, wherein the frames support the IGUs and related wiring.
 21. The network of claim 1, wherein the window controller is positioned within about 1 meter of the electrochromic pane for each window assembly.
 22. The network of claim 21, wherein the window controller is positioned within about 0.5 meter of the electrochromic pane for each window assembly.
 23. The network of claim 22, wherein the window controller is positioned within about 0.25 meter of the electrochromic pane for each window assembly.
 24. The network of claim 1, wherein the window controller directly controls the at least one electrochromic pane of the window assembly by controlling a pulse width modulated amplifier that generates current at high and low output levels to power the at least one electrochromic pane.
 25. The network of claim 1, wherein the drive configuration parameters comprise one or more parameters selected from the group consisting of: bleach to color transition ramp rate, initial coloration ramp rate, color to bleach transition ramp rate, and initial bleach ramp rate.
 26. The network of claim 1, wherein the drive configuration parameters comprise one or more parameters selected from the group consisting of: bleach to color transition voltage, initial coloration voltage, coloration hold voltage, color to bleach transition voltage, initial bleach voltage, and bleach hold voltage.
 27. The network of claim 1, wherein the drive configuration parameters comprise one or more parameters selected from the group consisting of: initial coloration current limit, coloration hold current limit, initial bleach current limit, and bleach hold current limit.
 28. The network of claim 1, wherein the window controllers reside along two, three, or four edges of the IGU, each within the secondary seal.
 29. A network comprising: (a) two or more window assemblies, each comprising: at least one electrochromic pane provided in an insulated glass unit (IGU), the IGU comprising the electrochromic pane, at least one additional pane, a sealing separator between the electrochromic pane and the at least one additional pane, and a secondary seal which incorporates a window controller; the window controller comprising circuitry for processing digital signals, the window controller configured to directly control said at least one electrochromic pane of the window assembly, wherein the window controller is positioned at least partially between the electrochromic pane and the additional pane of the IGU in the secondary seal; and a window frame housing said at least one electrochromic pane and the window controller; (b) a network controller communicatively coupled to the window controllers; and (c) an electrical path connecting the window controllers in a daisy chain.
 30. The network of claim 29, wherein the window controllers reside along two, three, or four edges of the IGU, each within the secondary seal. 